• Separate the yolks from the whites and set aside to let them come to room temperature while you prepare other things
• Spray the baking pan, 9 x 13 x 1 inch, with non-stick cooking spray or brush some oil and then line with a parchment paper on the bottom and the side

Cut the mangoes:

• Cut close to the stone on 4 sides. Use the pointy part of the knife to cut criss cross on the surface and then flip the mango up and use the knife to scrape the bottom part to release the mango cubes. Save about 1 cup for filling and about 8 cubes for decoration. You can puree the rest. You will need 60 grams for the cake batter and 45 grams for the whipped cream

Prepare cake batter:

• Preheat oven to 350 F (180 C) for conventional oven. For convection oven, lower the temperature by 20 F or 15 C. In a large mixing bowl, whisk egg yolks, oil, sugar, mango puree and milk until combined. Sift in the cake flour, and salt. Whisk to mix until combined and no lumps

Prepare the meringue:

• Place egg whites in a mixing bowl of a stand mixer fitted with a whisk attachment. Whisk until foamy on medium speed and then whip until foamy and add vinegar and whip again for another minute then and 1/3 of the sugar and continue to add sugar until you use it all up. Whip until the egg white develops a medium-soft peak. When you lift the meringue up it will hold up its shape a bit but still at the soft side and the tail will bend. Do not whip until stiff peak. The cake will crack when you roll it later

Fold meringue into the cake batter:

• Fold about 1/3 of the meringue into the egg yolk batter using a whisk to gently fold and mix and continue to fold in the next 1/3. On the last 1/3, use a rubber spatula and use the swipe down fold over motion to make sure you scrape the bottom of the bowl so that no cake batter left underneath. The batter should be light, fluffy, silky and smooth. You shouldn't see any more white meringue. The batter should be a pourable consistency
• Pour the batter into the pan and use a rubber spatula to help to spread evenly. Give the pan a litte jiggle to even out the batter. You can use a dough scraper to help you even out the surface too if necessary

Bake:

• Gently tap the baking sheet on your working surface several times to pop any air bubbles. Bake in a preheated oven at 350 F (180 C) for 25-30 minutes and then switch to convection mode (fan mode) and bake for another 3-4 minutes or until the top is golden brown and dry to touch. If you don't have convection mode, bake another 5 minutes and check to make sure the top is golden brown and dry to touch. It is important that the top is dry to touch so this layer won't peel off when you roll later

Prepare the mango cream:

• Put the heavy whipping cream, mango puree,and icing sugar in a mixing bowl. Use a mixer to whip until it is medium stiff. Don't whip it all the way stiff. Cover and keep it chilled in the refrigerator. Save about 1/3 cup to pipe the whipped cream on top for decor if you like

Cool down:

• Remove the cake from the oven and then lift it out from the pan immediately to a cooling rack and peel off the parchment paper from 4 sides. This helps to prevent wrinkles on the surface. Let it cools down like this for 10 minutes (I use a timer to actually time it)
• Place a new piece of parchment paper, larger than the cake, on top of the cake and flip over to the other side. Peel off the parchment paper

Trim the edges:

• Use a serrated knife to trim about 1/4-inch of the 4 edges. This makes rolling the cake easier because the edges are usually crusty and hard

Fill the cake:

• Decide if you will roll from the long side or short side. Use a serrated knife to trim about 1/4-inch of the 4 edges from the side you will start rolling. This makes rolling the cake easier
• Put the mango cream on the middle of the cake and spread it out a bit, but there's no need to spread the cream on the entire surface of the cake (refer to photo above). Put some cubes of mango on top of the cream

Roll the cake:

• Very gently use one hand to lift the parchment paper up to help you roll the cake up until you reach the other side. Tighten the roll up by pulling the parchment paper at the bottom and tucking in the paper on top using the dough scraper

Remove the parchment paper immediately:

• Now, most people will keep it rolled in a parchment paper this way and store it in the fridge to let it chills for 2-3 hours before slicing. I don't want to do that because the skin will peel right off after that. The condensation will form and makes the skin wet
• Remove parchment paper. Very gently place the cake on the serving plate you plan to serve. You can seal both ends with a bit of the mango cream. This helps to prevent the cake from drying. Loosely tent with a parchment paper, not touching the surface of the cake. Store in the fridge for at least 1 hour before you plan to cut the cake. I keep it in the fridge like this until the next day and the cake is perfectly moist and the skin is intact

To serve:

• Trim off about 1/4 inch from both ends. Pipe some whipped cream on top and place one cube of mango on each piped whipped cream. This is optional. Then slice the cake into slices in whatever size you like.
• Keep any leftover in the fridge, covered with wrap for maximum of one week